Paint composition



106. COMPOSITIONS,

COATING OR PLASTIC.

UNITED STATES" Examiner PATENT OFFICE" PAINT COMPOSITION Herman A.Scholz, Oak

Park, and Osborne Haydon, Chicago, 111., assignors to United StatesGypsum Company, Chicago, 111., a corporation of Illinois No Drawing.Application October 22, 1931,. Serial No. 570,502

11 Claims.

This invention relates to a paint composition, and has reference moreparticularly to a paint composition in powdered form adapted to be mixedwith water before application.

In the copending application of Herman A. Scholz, Serial 428,490 filedFebruary 14, 1930, a paint composition was described which was suitablefor use for exterior purposes. This composition contained among otheringredients, hydrated lime in excess with a minor proportion of Portlandcement. While this composition proved efiective for the purposeintended, the present application deals with a composition in which thePortland cement is in excess and the lime is in 1 minor proportion. Thepresent invention also omits some of the fillers disclosed in saidapplication. The composition to be hereinafter described is superior tothe composition described in said application in that it sets morerapidly, becomes harder, and has a less tendency to dust afterapplication. I

An object of the invention therefore is to provide a composition for awater paint in which the paint sets more rapidly, becomes harder and hasa less tendency to dust after application than paints commonly used forthis purpose; also to improve paint compositions in other respectshereinafter specified and claimed.

Our preferred formula for the paint composition is as follows:

Per cent White Portland cement (waterproof) 62.5 High calcium hydratedlime 31.1 Irish moss (powdered) .1 Salt (NaCl) '6.0 Calcium acetate(Ca(C2HsO2)z) .3

The hydrated lime should be white in color and is preferably of highcalcium lime, but a dolomitic lime may be used. It acts both as apigment and as a binding agent. It may vary in proportion from 20% toWaterproof white Portland cement is preferred, but ordinary whitePortland cement may be used and the waterproofing, such as calciywgate,added separately to the extent6i"2'% ased upon the cement. Ordinary grayPortland cement or other hydraulic cement may be used in the darkershades where the color does not become objec tionable. This ingredientis a binding and hardening agent and also acts as a pigment. This may bevaried between and 75% of the composition.

The salt (sodium chloride) or other soluble (c1. 134-40) l S chlorides,should be a good grade and as free as possible from deliquescentimpurities- Since it is a highly ionized electrolyte, it prevents theformation of excessive colloidal g'ilTEytIieIiifie' and Portland cement.It also hastens" the set 5 of the. paint and improves the hardness andthe bond. This may vary between 2% and 8%- andmay be replaced bypotassium chloride or other soluble chlorides.

Thelrish moss (chondrus) prevents settling of 10 the mixed paint. It maybe replaced by pectin, agar-agar or similar agents producing gels. Theaniountmay be decreased to .05%, increased to 0.5%, or the ingredientmay be entirely eliminated.

cmretards the formation of Excessive colloidal gels by t e ime aPortland cement in the wet mix, and thus lengthens the applicationperiod of the paint. It may be replaced by other inorganic acetates suchas zinc 2 acetate or sodium acetate It may be varie in proportion rom oo 1.0%.

The ingredients of our composition may be mixed in any desired order.The dry mixture is mixed with water to desired painting consistency andmay be sprayed or brushed onto a surface to be coated. Usually about -90pounds of water are necessary for pounds of the dry mixture.

As indicated in the above preferred formula, we prefer a ratio ofPortland cement to lime of 2:1 when we use a high calcium, hydratedlime. However, we do not wish to be confined strictly to that ratio, aswe desire in some cases to raise the proportion of lime somewhat, suchas when we use a dolomitic lime instead of a high calcium lime.Similarly, we may, when using a gray Portland cement, which is alkaline,instead of white Portland cement, which is neutral, raise the ratio ofPortland cement content in order to get the desired results. Thus the2:1 ratio may vary somewhat due to possible changes in raw materials inorder to balance the formula.

This paint is suitable only for application to clean, porous surfacessuch as stucco, cement, brick, tile, etc. Like cement or lime, it has arather low elasticity, but becomes an integral part of a material with aporous surface when the coeflicient of expansion is nearly the same. Itwill not adhere to wood or metal or to greasy surfaces, or surfaceswhich have been painted with oil or casein paint, or paints with otherorganic binders.

While the above description constitutes a practical embodiment of ourinvention, we do not wish to limit ourselves precisely to these details,since manifestly, the same may be considerably varied without departingfrom the spirit of the invention as defined in the appended claims.

Having thus described our invention, we claim as new and desire tosecure by Letters Patent:-

1. A coating composition comprising a dry mixture of hydraulic cement inmajor proportion, hydrated lime in minor proportion, soluble chloride,and anuetaLfrom the group consisting of calcium, zinc, and sodiumacetates.

2. A coating composition comprising a dry mixture of a major proportionof hydraulic cement, hydrated lime, a gel'forming substance from thegroup Irish moss, pectin and agar-agar, a soluble chloride, an acetatefromthe group consisting of calcium, zinc, an odium acetate. c mgcomposition comprising a dry mixture of hydraulic cement in majorproportion, hydrated lime in minor proportion, a soluble chloride, anacetate from the group consisting of calcium, zinc, and sodium acetatesand -90 lbs. of water per lbs. of the dry mixture.

- 4. A coating composition comprising a dry mixture of Portland cementin major proportion, hydrated lime, Irish moss, salt and calciumacetate.

5. A coating composition comprising a mixture of hydraulic cement inmajor proportion, hydrated lime, Irish moss, salt and calcium acet'ate.

6. A coating composition comprising a mixture of Portland cement inmajor proportion, hydrated lime, salt and 0.l-1% zinc acetate.

7. A coating composition comprising a mixture of hydraulic cement inmajor proportion, hydrated lime, 2-8% salt and 0.1-l% sodium acetate.

8. A coating composition comprising hydraulic cement and hydrated limein proportions of 2:1 respectively, a soluble chloride and an acetatefrom the group consisting of calcium, zinc, and sodium acetates.

9. A coating composition having approximately the following composition:

Percent White Portland cement (waterproof) 62.5 High calcium hydratedlime 31.1 Irish moss (powdered) .1 Salt (NaCl) 6.0 Calcium acetate(Camel-I102) 2) .3

10. A paint composition comprising the following ingredients in theproportions named:-

Percent Portland cement 50-70 Hydrated m 20-35 Soluble chloride 2-8Inorganic acetate 0.1-1.0

Percent Portland cement 50-70 Hydrated lime 20-35 Soluble chloride 2-8Inorganic acetate (1.1-1.0 HERMAN A. SCHOLZ.

OSBORNE HAYDON.

